Spinal Implant Bearing Surface Relief Pattern
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Solution Overview
Problem
Existing spinal implants experience unwanted movement relative to vertebrae due to external forces, particularly during the 6 to 12 months post-surgery fusion period, which can disrupt the therapeutic effect and bone fusion process.
Innovation Solution
A spinal implant with bearing surfaces featuring a relief pattern of conically shaped protrusions that inhibit movement in all directions, manufactured using selective laser sintering with polyaryletherketone (PAEK) powder materials, ensuring a secure fit and stability between the implant and vertebrae.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional smooth bearing surfaces are used on spinal implants, then manufacturing is simple, but the implant moves relative to vertebrae under external forces during fusion
Solution Approach 1:
The patent applies a relief pattern with protrusions and recesses on the bearing surfaces, creating a porous-like structure that increases mechanical interlocking between the implant and vertebrae. This structure prevents implant movement while maintaining biocompatibility and promoting bone fusion during the 6-12 month fusion period.
Solution Approach 2:
The relief pattern features rounded protrusions with curved surfaces rather than sharp edges. This curvature distributes contact stresses more evenly across the bearing surface, reduces stress concentration points, and maintains mechanical interlocking effectiveness while preventing implant migration under external forces.
2Reliability
If linear grooves and ridges are formed on bearing surfaces, then movement inhibition in one direction is improved, but movement in other directions remains uncontrolled
Solution Approach 1:
The bearing surface is segmented into multiple protrusions distributed across the surface, each capable of providing mechanical interlocking. This segmentation allows the surface to resist movement forces from multiple directions simultaneously, unlike linear grooves that only address movement perpendicular to their orientation.
Solution Approach 2:
The protrusions have asymmetric three-dimensional shapes with varying heights and orientations, allowing them to engage with the vertebrae in multiple directions. This asymmetric geometry provides omnidirectional movement inhibition while maintaining a relatively simple overall bearing surface design.
3Reliability
If pyramids are used on bearing surfaces, then movement inhibition in lengthwise and widthwise directions is improved, but vertical movement and other directions remain uncontrolled
Solution Approach 1:
The relief pattern uses localized protrusions with specific three-dimensional geometries distributed across the bearing surface. Each protrusion is optimized to provide mechanical interlocking in multiple directions, creating local quality enhancement without requiring complex overall surface structures or multiple different component types.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The spinal implant effectively prevents movement in all directions, enhancing the precision and stability of the implant's positioning, thereby improving the therapeutic outcome and bone fusion process.
Implementation Method 1
a method of using selective laser sintering to manufacture a spinal implant having the bearing surface
Data Source
AI summary
A spinal implant is provided that includes a body extending in direction at least substantially along a body axis, between a first end portion and a second end portion. The spinal implant also includes a first bearing surface disposed relative to the first end portion, and defining a first relief pattern that is configured to inhibit movement of the spinal implant relative to one or more vertebrae in at least substantially all directions. A method for manufacturing the spinal implant involves use of selective laser sintering.